• 1.0 baseline — 0.6 × season 1.0 (5 gm) + 0.4 × last 5 1.0
• +0.1 opponent leak — they concede 60.8/game vs a 56.6 league average
• vs them: averages 1.0 over 1 game — evidence, never summed

Derived, not measured — plain arithmetic over his real games, shown in full. Adjustments can overlap (a game at this ground can also be a wet one); they add simply, and this note is the admission.